As he read each line, a recorder in the book captured his voice for his 8-year-old daughter and 4-year-old son to listen to while he's away. When he finished, a USO volunteer popped the book into a package to try to get it to his home in West Richland, Wash., in time for Christmas.

Greer made the recording as part of the San Diego, Calif.-based United Through Reading's military program, which gives parents the chance to record themselves reading a book to their children while they are deployed. Various organizations donate books to the effort so they can be sent along with a DVD of the parent reading the book. This winter, Illinois-based Publications International Ltd. donated about 5,000 books for the cause.

Greer, who recorded himself reading another book before he left home and has given his son a bear containing his recorded voice, says those things help when the kids are having a hard time because of his absence.

"They've got something to remind them of Dad," said Greer after recording his voice on the Christmas book in an area of the airport run by USO volunteers that's located just off a busy terminal and features colorful children's decorations and walls lined with books.

Sally Ann Zoll, chief executive of United Through Reading, said the nonprofit, founded in 1989, started reaching out to military families during the first Gulf War but that it's been in the last few years that they've seen the most growth. Since the program started they've served more than one million, including the service members who read the books and the family members who received them. This year alone, they've served about 300,000.

Zoll says that not only do families bond through reading, but it also helps the child in school.

"There's a ton of research that tells us that reading aloud to a child is the most important indicator of success once they get to school," she said.

United Through Reading offers recording sites at about 130 military commands, about half of which are Navy ships, and at about 80 USO centers around the word. The recordable books are being offered at about 10 sites this winter, including on two Navy ships.

"The greatest thing you can give a soldier, airman or Marine is a connection to home," said Linda Robinson, volunteer coordinator at the USO at Dallas-Fort Worth International Airport, which is located in Grapevine, midway between Dallas and Fort Worth.

Cara Kisby said that her husband, Maj. Doug Kisby, recorded himself reading "'Twas the Night Before Christmas" at the USO at the Baltimore airport before he was deployed to Afghanistan last month. The book has proved to be a big hit with their 3-year-old, the youngest of their five children.

"She takes it everywhere: to the grocery story, the park. It's been a really nice thing for her to have, to have daddy's voice with her," said Kisby, of Woodbridge, Va., who said it was the third time her husband was deployed over Christmas.

She said even her oldest, an 11-year-old, will sit down and read the book with the 3-year-old.

"I think even for me, to hear his voice reading it to them, it kind of brings a calming atmosphere into the home," she said.

Before leaving for Iraq this week, Staff Sgt. Justin Conway, based at Kansas' Fort Riley, sat down at the Dallas airport's USO to down to read "Guess How Much I Miss You" for his seven-year-old daughter and one-year-old son. On his last deployment, he'd also done a DVD of himself reading another book, which became a fast favorite to his daughter.